Segment Information (Summary Of Segments Information) (Detail) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2020	Sep. 30, 2019	Dec. 31, 2019
Segment Reporting [Abstract]
Operating Expenses	$ 8		$ 87
Segment Reporting Information [Line Items]
Assets Under Vehicle Programs	10,043		10,043		$ 13,815
Revenues	1,534	$ 2,753	4,047	$ 7,010
Adjusted EBITDA	220	471	$ (249)	645
Document Fiscal Year Focus			2020
Non-vehicle related depreciation and amortization	74	62	$ 214	195
Interest expense	64	49	163	139
Early extinguishment of debt	(2)	(10)	(9)	(10)
Non-operational charges related to shareholder activist activity			4	0
Transaction-related costs, net	0	0	3	6
Restructuring and other related charges	17	22	89	66
COVID-19 Charges	10	0	90	0
Income before income taxes	53	328	(821)	273
Equity Method Investment, Realized Gain (Loss) on Disposal			0	(44)
Operating Expenses	8		87
Selling, general and administrative	166	350	549	947
Unusual or Infrequent Item, or Both, Net (Gain) Loss	19		14
Operating Leases, Rent Expense, Minimum Rentals	11		41
Supplies Expense	18		35
Vehicle depreciation and lease charges, net	256	551	1,089	1,579
Selling, General and Administrative Expenses [Member]
Segment Reporting Information [Line Items]
Selling, general and administrative	1		2
Vehicles deprecation and lease charges, net [Member]
Segment Reporting Information [Line Items]
Vehicle depreciation and lease charges, net	1		1
Americas [Member]
Segment Reporting Information [Line Items]
Assets Under Vehicle Programs	7,800		7,800		10,500
Revenues	1,114	1,868	2,936	4,822
Adjusted EBITDA	222	321	(41)	508
International [Member]
Segment Reporting Information [Line Items]
Assets Under Vehicle Programs	2,200		2,200		$ 3,300
Revenues	420	885	1,111	2,188
Adjusted EBITDA	6	169	(174)	187
Corporate and Other [Member]
Segment Reporting Information [Line Items]
Revenues	0	0	0	0
Adjusted EBITDA	(8)	(19)	(34)	(50)
Americas [Member]
Segment Reporting Information [Line Items]
Revenues	$ 1,114	$ 1,868	$ 2,936	$ 4,822